Metal springboard



Dec. 16, 1958 R. c. RUDE METAL SPRINGBOARD Filed Jan. 17. 1955 INVEN TOR. RAYMOND C. RUDE A T TORNEKS' w i IEvE lIiW i av Unite This invention relates to metal springboards of the type used in private and public swimming pools. This application is a continuation-in-part of my co-pending application Serial No. 388,316 filed October 26, 1953, now Patent No. 2,805,859 and entitled Metal Springboard.

In my co-pending application I described and claimed a metal springboard which, in one embodiment, comprised a flat top plate having a plurality oflongitudinally extending transversely spaced ribs formed integrally with the undersurface of the plate and defining a plurality of downwardly opening spaces. A board of this type may be extruded as a single piece or as two longitudinal sections flanged together along a longitudinal centerline to effectively form a unitary ribbed plate as described.

I have now found that a springboard of the type described in my co-pending application and particularly the embodiment mentioned above is further improved in its properties of balance and resistance to twist by provision of a torsional brace cooperating with the integrally formed ribs to provide an optimum degree of structural stability without detriment to fiexure and other functional characteristics of the board.

As mentioned above, the board may be extruded or otherwise formed with the top plate and parallel ribs as a single integral unit or in two longitudinal sections adapted to be fastened together along the longitudinal centerline of the board. In either event, the torsion brace is a separate upwardly opening channel-shaped rrember extending longitudinally of the board and fastened to the underside of the board along the opposite longitudinal edges of the brace. Briefly, the brace is symmetrically disposed about the centerline of the board and lies between the innermost pair of parallel ribs.

In the event the board is fabricated of two longitudinal sections flanged together along the longitudinal centerline, the torsional brace conveniently encloses the flanged connection.

lt is important that this brace enclose, with the undersurface of the board, a certain volume in order to develop the desired torsional resistance. I have found that this enclosed volume should be in the order of that developed by a channel-shaped brace member having a uniform cross-section of approximately four square inches extending from end to end of the board. The total volume enclosed by a torsional brace of this size extending from atent ice 2 I I Fig; 2 is a longitudinal sectional elevation taken on the line 22 of Fig. 3;

Fig. 3 is a transverse sectional elevation taken on the line 33 of Fig. 1;

' Fig. 4 is an end elevation of the board of Fig. 1 and .Fig. 5 is a transverse section of a springboard in accordance with an alternative embodiment of the inven-' alloys or materials mentioned in my co-pending applicaend to end of a 16 foot board will, of course, be greater than that of a like brace extending from end to end of a 10 or 12 foot board. However, this cross-section of approximately four'square inches can be taken as a preferred minimum regardless of the board dimension.

The invention will be clearly understood from the fol lowing detailed description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a side elevation partially in section of a board in accordance with the invention, showing a part of the anchoring and fulcrum means;

'row downwardly opening longitudinal spaces 34.

tion.

The plate 24 is of uniform thickness from end to end and has a plurality of ribs 26, 27, 28, 23, 30, 31, 32 and 33 formed integrally with its undersurface and projecting perpendicularly to the plane of the plate. The two outer ribs 26 and 33 define the longitudinal sides of the board. The three ribs 27, 28 and 29 are evenly spaced inwardly from the outer rib 26, the group of four ribs being formed nearer the outer edge of the board than they are to the center of the board. Similarly, the three ribs 30, 31 and 32 are evenly spaced inwardly from the longi tudinal outer rib 33 and this group is also formed closer to the outer edge of the board than the longitudinal centerline of the board. The ribs define a plurality of nar- A wider space 34A is defined by 'the innermost ribs 29 and 30.

Commencing at a point just forward ofthe fulcrum 12, the several ribs 26, '27, 28, etc. taper uniformly toward the outer end of the board, the section of Fig. 3 showing that at or adjacent the outer end of the board the ribs are of a height of less than half of their height at the fulcrum 12.

In accordance with the present invention, a torsion brace 35 is fastened along its longitudinal edges 36 and 37 to the underside of the plate 24 symmetrically about the longitudinal centerline of the board and lying between the inner ribs 29 and 30. The torsional brace is generally channel-shaped with sides 38, 39 terminating respectively in the lips 36 and 37 and connected by a central bottom portion 40. The bottom portion is preferably reverse channeled at 41 along its central axis for increased strength and may be provided as illustrated with longitudinal ribs 42, 43, 44, 45. The object of this construction is to obtain. a maximum of strength with a minimum of weight. The brace is preferably fastened to the underside of the board with a plurality of rivets '46, as illustrated, but other fastening techniques can also be employed.

As shown in Fig. 2 the torsion member 35 is of substantially uniform cross-section and extends from end to end of the board. In the region of maximum dimension of the ribs 26, 27, 28, etc. the ribs project outwardly from the bottom of the plate further than the torsion member. However, again as shown in Fig. 2, the tapered minimum volume. I have found that if the uniform cross-section of the torsion brace channel is at least about four square inches, a suflicient volume is enclosed throughout the length of the brace to provide the desired torsional reinforcement.

The embodiment of the springboard of the invention shown in transverse sectional elevation in Fig. 5 differs from that shown in Figs. 1 through 4 in the fact that it is fabricated from two substantially identical longitudinal sections. The two sections identified in the drawing with reference numerals and 51 are each provided with integrally formed reinforcing ribs identical in shape .and orientation with the ribs 26, 27, 28, etc. of the previously described board and the ribs define a plurality of longitudinally extending spaces identical to spaces 34 of the board .of Figs. 1 through 4.

In this embodiment the two sections 50 and 51 are provided along their inner longitudinal edges with flanges 52 and 53 respectively which may be joined together as by rivets 55 to form a single board of identical construction to that previously described save for the flanges and the longitudinal junction between the two sections. As in the foregoing embodiment a torsional brace 56 is provided anchored along its longitudinal edges to the undersurface of the board, the edges being equidistant from and on opposite sides of the centerline of the board and the brace being disposed between the innermost integral ribs. In this construction it is important that the brace 56 be spaced from the lower edge of the flanges 52 and 53 so that the twist stability developed by the brace is not interfered with by structural engagement of the brace and flanges. An occasional contact between the brace and flanges 52 and 53 when the board is flexed is in no way detrimental.

Another important feature of the board, as illustrated, is the cross-sectioanl shape of the reinforcing ribs. As shown in Figs. 3 and 5, the ribs taper from a relatively narrow neck at the undersurface of the top plate to a considerably thicker outer edge. Under load, the plate .is under tension and the outer edge of each of the ribs is under compression. The intermediate portion of the rib represents a neutral axis and a great deal of weight is saved without impairing the strength of the board by minimizing the amount of metal in the region of the neutral axis.

Still another very important advantage results from the preferred cross-sectional shape of the ribs. As the height of the ribs decreases toward the outer end of the board,

there is in effect a compound taper. This results in a distribution of flexibility away from the fulcrum point which is of great advantage in both function and durability.

As described in greater detail in my co-pending application referred to above, and as shown in the sectional elevations of Figs. 3 and 5, the top plate of the board of the invention may be provided with a friction-surfacing material identified as 58 in Fig. 3 and as 60 in Fig. 5. Preferably this surfacing material consists of a plurality of narrow abrasive strips disposed transversely across the board in uniformly spaced relation and from end to end of the board. The present invention in no way relates to the surfacing of the board and is not limited to the particular surfacing mentioned or to any friction surfacing.

I claim:

1. A metal springboard adapted to be supported at one end by anchoring means and between its ends by fulcrum means, the board comprising a top plate having a flat upper surface extending from end to end of the board, a plurality of longitudinally extending spaced parallel ribs formed integrally with the underside of the top plate and defining a plurality of downwardly opening longitudinal spaces, said ribs being displaced outwardly from either side of the longitudinal centerline of the plate, and an upwardly opening channel-shaped torsion brace anchored to the underside of the board and extending longitudinally thereof and between the innermost ones of said ribs.

2. A metal springboard adapted to be supported at one end by anchoring means and between its ends by fulcrum means, the board comprising two substantially identical elements each comprising a top plate having a flat upper surface extending from end to end of the board, a plurality of longitudinally extending spaced parallel ribs formed integrally with the top plate and on the underside thereof and defining a plurality of downwardly opening spaces, a flange depending from one longitudinal edge of the top plate, means fastening the flanges of the two elements together with the top plates coplanar, and an upwardly opening channel-shaped torsion brace anchored to the underside of the board and enclosing the flanges of the top plate.

3. A metal springboard adapted to be supported at one end by anchoring means and between its ends by fulcrum means, 'the board comprising two substantially identical longitudinal half sections with each section comprising a top plate having a flat upper surface extending from end to end of the board, a plurality of longitudinally extending evenly spaced parallel ribs formed integrally with the top plate and on the underside thereof, the ribs being displaced toward the outer edge of the plate with one rib coinciding with the outer edge of the plate, a flange depending from the inner edge of the plate, means joining the flanges of the two sections together with the top plates coplanar, such joint defining the approximate longitudinal centerline of the board, and a channelshaped torsion brace anchored along each of its longitudinal edges to the underside of the board on opposite sides of the joined-together flanges whereby the torsion brace encloses the flanges from end to end of the board.

4. A metal springboard adapted to be supported at one end by anchoring means and between its ends by fulcrum means, the board comprising a top plate having a flat upper surface extending from end to end of the board, a plurality of longitudinally extending spaced parallel ribs formed integrally with the top plate and on the underside thereof, the ribs increasing in lateral thickness outwardly from the region of the juncture of the ribs with the under surface of the plate, and a channelshaped torsion brace anchored to the underside of the board symmetrically about the longitudinal centerline of the board.

References Cited in the file of this patent UNITED STATES PATENTS 1,574,563 Duff Feb. 23, 1926 1,574,586 Loucks Feb. 23, 1926 1,710,350 Dewoitine Apr. 23, 1929 2,235,883 John Mar. 25, 1941 2,461,086 Schumacher Feb. 8, 1949 2,478,993 Wing Aug. 16, 1949 2,485,165 Pollman Oct. 18, 1949 2,649,304 Ulanovsky Aug. 18, 1953 2,694,475 Crafton Nov. 16, 1954 2,747,871 Brandt et cl May 29, 1956 

